Samsung patents method to sync signal beams across multiple carriers

1. A method performed by a terminal in a wireless communication system, the method comprising: receiving, from a base station, a radio resource control (RRC) message containing a first list and a second list that are lists for serving cells to which to apply simultaneously an update of a transmission configuration indicator (TCI) state; receiving, from the base station, a medium access control (MAC) control element (CE) containing a serving cell identifier (ID), a control resource set (CORESET) ID, and one or two TCI state IDs; based on a logical channel ID (LCID) associated with the MAC CE, identifying whether the MAC CE is a first MAC CE indicating one TCI state or a second MAC CE indicating two TCI states; in case that the MAC CE is the first MAC CE, receiving, from the base station, a physical downlink control channel (PDCCH) by applying the one TCI state to all cells in the list in which a serving cell is contained, in case where the serving cell indicated by the MAC CE is contained in the first list or the second list; and in case that the MAC CE is the second MAC CE, receiving, from the base station, the PDCCH by applying the two TCI states to all the cells in the list in which the serving cell is contained, in case where the serving cell indicated by the MAC CE is contained in the first list or the second list, wherein the first list and the second list are used both when the MAC CE is the first MAC CE and when the MAC CE is the second MAC CE.